1. Field of the Invention
The present invention relates to a dialysis system and a method of cleaning and priming a blood circulation path of the dialysis system. More particularly, the invention relates to a dialysis system capable of using a dialysate in place of physiological saline as a replenisher solution when blood pressure is lowered and capable of using a dialysate in place of physiological saline in a cleaning and priming operation and in a blood returning operation in blood dialysis treatment, and relates to a method of cleaning and priming of the dialysis system.
2. Description of the Prior Art
A dialysate is used in blood dialysis. Air or filled sterilized water is contained in a dialyzer before the dialyzer is used in blood dialysis and the air or the sterilized water needs to be removed. Therefore, as a pretreatment, conventionally, the inside of a dialyzer and the inside of a blood line connected to the dialyzer (hereinafter, referred to as the inside of a blood circulation path) are cleaned and primed by using, for example, physiological saline (normally, about 500 through 1000 ml).
Further, after finishing blood dialysis, blood remaining in the inside of the blood circulation path needs to be returned into the body of a patient who has undergone the blood dialysis treatment (referred to as blood returning) as much as possible, and as a post treatment, conventionally, blood is returned into the human body by using, for example, physiological saline (about 300 ml).
However, since physiological saline is expensive, a conventional blood dialysis system using a large volume thereof is problematic because of the considerable cost of the blood dialysis.
Hence, in order to resolve such a drawback, there have been proposed a method and an apparatus of blood dialysis (Japanese Unexamined Patent Publication No. 80346/1996) capable of achieving a reduction in the cost of the blood dialysis by reducing the volume of physiological saline used in the priming and blood returning operations, and a physical solution treating apparatus (Japanese Unexamined Patent Publication No. 150201/1996) capable of using a dialysate in place of physiological saline used in the priming and blood returning operations.
According to the blood dialysis system of Japanese Unexamined Patent Publication No. 80346/1996, when a blood dialysis operation is stopped, dialysate from a dialysate supply source is filtered to clean the dialysate and the provided filtered dialysate is pressurized from a dialysate flow path of a dialyzer to a blood flow path through dialysis membranes constituting a dialysis element. However, according to the method, in respect of blood remaining in a blood circulation path upstream from the blood flow path, the blood needs to be pushed out to the blood flow path by using physiological saline. Thus, despite the improvement, there is a drawback in that a necessary volume of physiological saline needs to be prepared and the operation takes time and labor.
Meanwhile, according to the physical solution treating apparatus of Japanese Unexamined Patent Publication No. 150201/1996, a dialysate reservoir bag is connected to an intermediate point of an artery side line through a branch tube and a dialysate in the dialysate reservoir bag can be transferred to prime a blood chamber and a vein side line through the artery side line. However, according to the method, there are drawbacks in that not only is the dialysate reservoir bag expensive but also an operation of filling the dialysate into the bag becomes necessary and the operation is troublesome.
Further, there is a case in which a replenisher solution (normally, physiological saline is used) is infused into the body of a patient when the blood pressure of the patient is lowered during blood dialysis treatment and in infusing the replenisher solution, conventionally, there are adopted methods, for example, as illustrated in FIG. 7 and FIG. 8.
According to the method illustrated in FIG. 7, a replenisher solution supply source 105 is connected to a blood circulation path 101 and the replenisher solution is infused while stopping the blood dialysis operation. As the replenisher solution supply source 105, a bottle or a bag filled with sterilized replenisher solution is generally adopted. In replenishing the solution, a valve 106 is closed, a valve 107 is opened and the replenisher solution is infused from the replenisher solution supply source 105 into the blood circulation path 101 by a blood pump 104. Flow rate of the replenisher solution is determined by the blood pump 104. Further, in the drawing, numeral 100 designates a dialyzer and numerals 102 and 103 designate drip chambers.
According to the method illustrated in FIG. 8, a replenisher solution line 209 is separately provided and a dialysate in a dialysate circulation path 206 which is cleaned by endotoxin filters 207 and 208 is infused into a blood circulation path 201. The replenisher solution line 209 is provided with an endotoxin filter 211 for further cleaning the dialysate and the replenisher solution is infused by a replenisher solution pump 210. Further, in the drawing, numeral 200 designates a dialyzer and numeral 205 designates a closed-type water-removal control apparatus.
However, according to the method illustrated in FIG. 7, the replenisher solution needs to be prepared, the setup operation of connecting the replenisher solution supply source to the blood line and adding the replenisher solution (the case of a large volume of the replenisher solution) requires additional labor, and there are drawbacks in that there is a danger of erroneous operation or contamination since the replenishing operation is comparatively troublesome and that the cost is considerable.
Meanwhile, according to the method illustrated in FIG. 8, the dialysate is infused directly into the blood circulation path and accordingly, two of the endotoxin filters are normally needed and the cost is increased. Further, although the solution needs to be replenished when the blood pressure is lowered, according to the system of FIG. 8, water is removed by the dialyzer by a volume of the replenished solution and accordingly, there is a drawback in that the solution cannot be substantially replenished.